The key difference between NADH and NAD+ is that NADH has been shown to enter the cell and increase ATP energy production in the cell.

Consequently, if the cell has more energy, it can produce all molecules necessary for cell regulation in sufficient quantities.

NAD+ does NOT enter the cell and can therefore not form ATP. This has been proven in the study (1). Also the NAD+ precursors such as nicotinamide ribosides or NMN (nicotinamide mono nucleotides) do not pass through the cell membrane because they are both positively charged molecules. These molecules cannot penetrate the cell membrane’s lipid layer. This statement is clearly illustrated in the following diagram.

More than 50 scientific studies have been published about the biological functions and therapeutic effects of NADH, and there have also been many studies published about the safety and absence of side effects of NADH (2).

The following facts demonstrate the difference between NADH and NAD+: NAD+ has only been the subject of sporadic scientific studies. To date, a single study on the tolerability of NAD+ has been conducted using 8 (eight) healthy middle-aged people. The unsurprising result was that the 8 participants tolerated NAD+ well (3). Nevertheless, the NAD+ molecules are too large and therefore cannot diffuse through the cell membrane. It is also important to note that NAD+ in its pure form is NOT a nutrient and therefore cannot be taken with food or with food supplements (4).

Clinical studies show that NMN supplements increase NAD+ to a youthful level. NADH, however, is found in many types of food and is available as a dietary supplement around the world. NADH also has at least 3 scientifically proven anti-aging effects (5,6,7). There are 3 main phenomena responsible for aging: (a) Decrease of ATP – energy production in the cells. NADH increases ATP energy production in the cell (1) (b) Damage to the DNA as a result of environmental toxins, radiation and chemotherapy. NADH can repair DNA and cells that have been damaged (8). (c) Oxidation and damage to the cell membrane. NADH acts as a strong biological antioxidant (9). NAD+ being the oxidised form of NADH can NEVER act as an antioxidant.


1. “NADH-supplementation decreased pinacidil-primed I K(ATP) in ventricular cardiomyocytes by increasing intracellular ATP” Pelzmann B, Hallström S, Schaffer P, Lang P, Nadlinger K, Birkmayer GD, Vrecko C, Reibnegger G and Koidl B. Brit. J. Pharm. 2003 139,749-754.


3. “An open-label, non-randomized study of the pharmacokinetics of the nutritional supplement nicotinamide riboside (NR) and its effects on blood NAD+ levels in healthy volunteers”. Airhart, S. E., Shireman, L.M., Risler, L.J., Anderson, G. D., Nagana Gowda, G. A., Raftery, D., et al. (2017). PloS One 12:e0186459. doi: 10.1371/

4. Opinion no 018/2012 of the German Federal Institute for Risk Assessment (BfR) dated 06 February 2012

5. “Coenzym-1 (N.A.D.H.): A Proven Anti-Aging Substance” Birkmayer JGD, Abstr.Comm. 1st European Congress on Anti-Aging Medicine October 18 -21, 2006 Vienna, Austria

6. “Coenzym-1 (NADH) – Eine wissenschaftlich bewiesene Anti-Aging-Substanz” Birkmayer JGD, Prevention and anti aging 2006 340-348

7. “Method of prolonging the Life-span of Living Cells using NADH, NADPH and ADP-Ribose” Birkmayer JGD, Nadlinger K, Hallstöm S, Westerthaler W, US-Patent Pub.No. US 2004 / 0126751

8. The Reduced Coenzyme Nicotinamide Adenine Dinucleotide (NADH) repairs DNA damage of PC12 cells induced by doxorubicin; Zhang JR, Vrecko K, Nadlinger K, Storga D, Birkmayer GD, Reibnegger G J. Tumor Marker Oncol. 1998; 13, 5-17.

9. “The antioxidative capacity of ENADA®-NADH in humans”; Reibnegger G, Greilberger J, Juergens G. and Oettl K.J. Tumor Marker Oncol. 2003; 18, 37-41.